Seismic Energy Calculator

Model earthquake energy release using magnitude, distance, and efficiency. Compare reference events and attenuation instantly. Export results, tables, and charts for engineering reviews today.

Calculator Inputs

Earthquake Magnitude (Mw)

Reference Magnitude

Epicentral Distance (km)

Focal Depth (km)

Attenuation Exponent

Capture Efficiency (%)

Shaking Duration (s)

Energy Comparison Chart

This Plotly chart compares magnitude levels with estimated released seismic energy in joules.

Example Data Table

Scenario	Magnitude	Distance (km)	Depth (km)	Energy (J)	TNT (tons)
Small regional event	4.2	18	8	1.9953e+11	47.6897
Moderate structural concern	5.5	30	14	1.1220e+13	2681.6440
Strong design reference	6.8	45	20	6.3096e+14	150803.0593

Formula Used

1) Seismic energy from magnitude

log10(E) = 1.5M + 4.8

E = 10^(1.5M + 4.8)

2) Energy ratio between two magnitudes

Energy Ratio = E / Eref

3) Hypocentral distance

R = √(epicentral_distance² + focal_depth²)

4) Surface energy flux index

Flux = E / (4πR²)

5) Attenuated energy index

Attenuated Index = E / R^n

6) Captured energy

Captured Energy = E × efficiency

7) TNT equivalent

TNT tons = E / 4.184 × 10^9

These relations provide a practical engineering estimate. They help compare events, estimate relative release, and build quick screening studies.

How to Use This Calculator

Enter the earthquake moment magnitude.
Set a reference magnitude for relative comparison.
Provide epicentral distance and focal depth values.
Choose an attenuation exponent for your study model.
Enter capture efficiency if estimating usable or measured energy.
Input shaking duration to estimate average power.
Press the calculate button to view results above the form.
Download CSV or PDF files for reporting.

Frequently Asked Questions

1. What does this calculator estimate?

It estimates seismic energy in joules from earthquake magnitude. It also shows reference comparisons, TNT equivalent, attenuation indicators, hypocentral distance, captured energy, and average power.

2. Which magnitude scale is assumed?

The calculator is intended for moment magnitude style inputs. The energy equation is commonly used for broad earthquake energy estimation and comparison work.

3. Why compare with a reference magnitude?

Reference magnitude helps quantify how much larger or smaller one event is. Even a small magnitude increase can represent a very large energy increase.

4. What is the attenuation exponent for?

It provides a simple distance-decay model. Engineers can use it for relative site comparison, screening studies, or preliminary hazard communication.

5. Is the TNT conversion exact?

No. It is an equivalent energy comparison using TNT heat of detonation. It is useful for scale awareness, not for blasting design.

6. What is captured energy?

Captured energy is the selected percentage of total estimated seismic energy. It can represent measurable, recoverable, or instrumentally observed energy in a simplified study.

7. Can this replace a full seismic hazard analysis?

No. This tool is for quick engineering estimation. Detailed hazard work requires source mechanics, site response, structural models, and regional seismic data.

8. Why is average power included?

Average power divides total energy by shaking duration. It offers another way to compare event intensity over time during conceptual engineering review.